PDM example in SDK 15.3.0

RE: PDM example in SDK 15.3.0

Simonr — Tue, 16 Jul 2019 13:07:55 GMT

Could you please create a new ticket where you explain your problem, and what your application is supposed to do in order for us to get a better overview of what exactly is wrong. This will also ensure this ticket won't derail into something completely off-topic.

Thanks,

Simon

RE: PDM example in SDK 15.3.0

sara — Tue, 16 Jul 2019 12:42:38 GMT

And when I read the pdm documentation it says I need to change the PSEL.CLK register value? Then how should I do it and with what value? same for PSEL.DIN register. I am confused a lot. Please suggest me the solution to all my doubts.

RE: PDM example in SDK 15.3.0

sara — Tue, 16 Jul 2019 06:48:52 GMT

The error was solved, I had not enabled

#ifndef PDM_ENABLED
#define PDM_ENABLED 1

I programmed the code but now question is how should i check whether pdm is working properly or not? I am not storing anything in flash. For now, I just need the data of pdm so how should I test it to get the results

static void bsp_event_handler(bsp_event_t event)
{
    ret_code_t err_code;

    switch (event)
    {
        case BSP_EVENT_SLEEP:
            sleep_mode_enter();
            break; // BSP_EVENT_SLEEP

        case BSP_EVENT_DISCONNECT:
            err_code = sd_ble_gap_disconnect(m_conn_handle,
                                             BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION);
            if (err_code != NRF_ERROR_INVALID_STATE)
            {
                APP_ERROR_CHECK(err_code);
            }
            break; // BSP_EVENT_DISCONNECT

        case BSP_EVENT_WHITELIST_OFF:
            if (m_conn_handle == BLE_CONN_HANDLE_INVALID)
            {
                err_code = ble_advertising_restart_without_whitelist(&m_advertising);
                if (err_code != NRF_ERROR_INVALID_STATE)
                {
                    APP_ERROR_CHECK(err_code);
                }
            }
            break; // BSP_EVENT_KEY_0
          case BSP_EVENT_KEY_1:
            NRF_LOG_INFO("\n Press Button key 1\n");
            NRF_LOG_INFO("\n Erase the flash content !!\n");
//            err_code = pcm_pstorage_eraseall();
//            APP_ERROR_CHECK(err_code);
            break;

         case BSP_EVENT_KEY_2:
            NRF_LOG_INFO("\n Start:PDM --> PCM\n");
            err_code =  nrf_drv_pdm_start(); 
            APP_ERROR_CHECK(err_code);
            break;

         case BSP_EVENT_KEY_3:
            NRF_LOG_INFO("\n Stop:PDM --> PCM\n");
            // stop audio sample
            nrf_drv_pdm_stop();
            break;

        default:
            break;
    }
}









static void drv_audio_pdm_event_handler(uint32_t *p_buffer, uint16_t length)
{
	m_buffer_handler((int16_t *)p_buffer, length);
        int i;
//        for(i=0;i<= length;i++)
//        {
//          NRF_LOG_INFO("%s ",&p_buffer[i]);
//        }
//        NRF_LOG_INFO("\n ");
          NRF_LOG_INFO("pdm event handler \n");

}


uint32_t drv_audio_init(drv_audio_buffer_handler_t buffer_handler)
{
//    nrf_drv_pdm_config_t pdm_cfg = NRF_DRV_PDM_DEFAULT_CONFIG(CONFIG_IO_PDM_CLK,
//                                                              CONFIG_IO_PDM_DATA,
//                                                              m_pdm_buff[0],
//                                                              m_pdm_buff[1],
//                                                              CONFIG_PDM_BUFFER_SIZE_SAMPLES);
    nrf_drv_pdm_config_t pdm_cfg = NRF_DRV_PDM_DEFAULT_CONFIG(CONFIG_IO_PDM_CLK,CONFIG_IO_PDM_DATA);
    
    if (buffer_handler == NULL)
    {
        return NRF_ERROR_INVALID_PARAM;
    }
    
    m_buffer_handler    = buffer_handler;
    pdm_cfg.gain_l      = CONFIG_PDM_GAIN;
    pdm_cfg.gain_r      = CONFIG_PDM_GAIN;
    

    return nrf_drv_pdm_init(&pdm_cfg, drv_audio_pdm_event_handler);
}










int main(void)
{
    bool erase_bonds;

    // Initialize.
    log_init();
    timers_init();
    buttons_leds_init(&erase_bonds);
    power_management_init();
    ble_stack_init();
    gap_params_init();
    gatt_init();
    advertising_init();
    services_init();
    conn_params_init();
    peer_manager_init();

    // Start execution.
    NRF_LOG_INFO("Template example started.");
    application_timers_start();

//    advertising_start(erase_bonds);
    uint32_t err_code;
    err_code = drv_audio_init(drv_audio_pdm_event_handler);
    APP_ERROR_CHECK(err_code);
    
    // Enter main loop.
    for (;;)
    {
        idle_state_handle();
    }
}

.For your reference, I am attaching my code snippet

I have checked the clk pin on Oscilloscope , the clock is not being generated.In order to generate clk at pin number 22 of nrf52 DK board should I define pin clk as #define CONFIG_IO_PDM_CLK 0x22 or 0x16 (hex value of 22 )instead of 0x22?

RE: PDM example in SDK 15.3.0

sara — Tue, 16 Jul 2019 04:53:03 GMT

yes I have set the paths correctly.I have added #include "nrf_drv_pdm.h" in main .c file , then added the following in the .emProject file <file file_name="../../../../../../modules/nrfx/drivers/src/nrfx_pdm.c" /> is there anything else I am missing?

And I m using SES too. SDK ver 15.3.0

RE: PDM example in SDK 15.3.0

sarnab — Tue, 16 Jul 2019 04:45:05 GMT

Hmm, that is strange. What IDE are you using? I am on Segger Embedded Studio (SES). Are you sure your include paths are set correctly?

RE: PDM example in SDK 15.3.0

sara — Tue, 16 Jul 2019 03:49:29 GMT

yes it takes me to file to the file and when I right click on nrf_drv_pdm_start it takes me to its macro definition in nrfx_drv_pdm.h as nrfx_pdm_start

RE: PDM example in SDK 15.3.0

sarnab — Mon, 15 Jul 2019 23:55:42 GMT

when you right click on nrfx_pdm.h and select 'go to definition' does it take you to the file?

RE: PDM example in SDK 15.3.0

sara — Mon, 15 Jul 2019 23:52:42 GMT

Yes, I have included the nrfx_pdm.h but getting nrfx_pdm_init undefined and nrfx_pdm_start undefined references. For that what should I do?

RE: PDM example in SDK 15.3.0

sarnab — Mon, 15 Jul 2019 22:37:34 GMT

Hi Sara, I was able to get it working though I have not extensively tested if the data is valid. To get the nrfx_pdm_xxx() functions you have to include nrfx_pdm.h in your project. Hope that helps. Also if you are able to get meaningful data please let me know what you did!

RE: PDM example in SDK 15.3.0

sara — Mon, 15 Jul 2019 12:08:59 GMT

Hi, Sarnab I too, have the same question as yours. So how far have you reached?I tried the example which Simonr have provided the link for the example. But I am getting the following errors:

undefined reference to `nrfx_pdm_init' and undefined reference to `nrfx_pdm_start'

@ Simonr if you have any idea about how can I solve the above errors?

RE: PDM example in SDK 15.3.0

Simonr — Fri, 28 Jun 2019 07:33:48 GMT

No, I'm sorry but we do not have any tutorials using the PDM module and the SoftDevice S140. I still think the example from the last reply will be your best bet here. Or we could hope that someone in the community has done something similar before.

Best regards,

Simon

RE: PDM example in SDK 15.3.0

sarnab — Thu, 27 Jun 2019 18:53:38 GMT

Is there any other tutorial or example that uses the nRF52840 PDM module with the SD140?

RE: PDM example in SDK 15.3.0

Simonr — Tue, 25 Jun 2019 07:33:59 GMT

Hi Sarnab

I'm afraid we don't have a PDM example as part of our nRF5 SDK. However, this example for PDM in SDK 11 was made by one of my colleagues and should be usable in newer SDKs with some tweaks.

You could also check out the Thingy:52 SDK which uses the PDM audio drivers.

Best of luck and regards,

Simon